1. Field of the Invention
The present invention deals with snow guards used to prevent excessive amounts of snow and ice from falling off sloped roofs and injuring people or destroying property.
2. Description of the Related Art
Previous attempts by prior art at solving the problem of excessive amounts of snow and ice falling off roofs have failed for a variety of reasons. Some prior devices have used an inadequate way of fastening the snow catching device or "head" to the roof. Prior fabrications for the fastening device which will be referred to as the "strap" have produced devices which bend easily under the pressure of sliding ice and snow. U.S. Pat. No. 1,732,936 to Hudson and U.S. Pat. Nos. 3,296,750 and 5,343,659 to Zaleski employ the use of thin metal strips which are not sufficiently resistant to bending resulting in the head being disrupted from its proper position on the roof. When these straps fail, they usually do extensive damage to the roofing material they are installed beneath and fail to hold back snow and ice. U.S. Pat. No. 5,044,130 to Chiddister omits a strap entirely. The head is held by fasteners which penetrate the face of the roofing material. The disadvantage of this method is that creating holes in the roofing material gives a potential for leaks. Over time, water may seep into these holes, rotting away the roof.
Another area where prior art forms have failed is the means by which the head is fastened to the strap. Bolts and rivets have failed by deforming and shearing off under heavy loads. Many prior devices fail to provide adequate rigidity in the connection area between the head and the strap. This problem results in the head either shearing off or bending under the weight of the snow and ice slides.
The third area of prior art failure is the shape of the head. Many heads have a flat face which comes into contact with the sliding snow and ice. A flat abrupt face is ideal for catching snow and ice but results in tremendous loads being placed on the snow guard and does little to break up sheets of ice. These loads cause the failures already mentioned and require the heads to be made from thick material or cast from molten material which increases costs. A flat face head requires a rigid connection between itself and the strap, thereby complicating fastening details and increasing costs. Field observations of prior devices have shown failures in this area. Breaking up sheets of ice that slide down roofs has two benefits: first, smaller pieces of ice melt faster and second, the smaller pieces of ice are less likely to do damage if they fall from the roof. Flat face heads do very little to break up sheets of ice.